An iminodiacetic acid chelating resin has high capability of selectively adsorbing a heavy metal and is widely used in the fields such as heavy metal removal from salt and purification of chemicals.
As the production method of an iminodiacetic acid chelating resin, there have been conventionally known, for example, a method of synthesizing an aminomethylated polymer by the phthalimide process and reacting the polymer with chloroacetic acid (Patent Document 1), a method of reacting hexamethylenetetramine with a chloromethylated polymer to synthesize an aminomethylated polymer and reacting the polymer with chloroacetic acid (Patent Document 2), a method of reacting a chloromethylated styrene crosslinked copolymer with iminodiacetonitrile (Non-Patent Document 1), a method of reacting a chloromethylated styrene crosslinked copolymer with an iminodiacetic acid ester (Non-Patent Document 2), and a method using a chloromethylated styrene crosslinked copolymer as a raw material, wherein hydrophilicity is imparted to the matrix of the crosslinked copolymer by use of dimethylaniline as a catalyst and the copolymer is reacted with iminodiacetonitrile (Patent Document 3).
In this connection, in Non-Patent Document 1, a chloromethylated styrene crosslinked copolymer is reacted with iminodiacetonitrile by using pyridine as a solvent and then hydrolyzed.